The rainy season, characterized by extreme humidity and potential flooding, is a critical period for induction furnace operations. High-voltage electrical systems are exceptionally sensitive to moisture. If mishandled, dampness can lead to insulation breakdown, arcing, or even complete coil failure.
Below is an emergency guide for detecting and drying damp induction coils, pit cables, and busbars.
আমি. Precision Testing of Insulation Levels
During extreme weather, visual inspections are insufficient; data must drive the assessment.
- Megger Testing (অন্তরণ প্রতিরোধের):
- Coil-to-Ground Insulation: ব্যবহার a 2500ভি Megohmmeter to measure the insulation between the induction coil and the furnace frame/ground. The reading should ideally be above 10MΩ. If it falls below 0.5MΩ, powering up the equipment is strictly prohibited.
- Water-Cooled Cable Inspection: Check the rubber sleeves of the cables for water seepage or condensation. Since these cables are often located at the bottom of pits, submerged cable heads are the primary cause of electrical breakdown.
- Leakage Current Monitoring:
- Closely monitor the leakage current meter on the power supply cabinet. An abnormal rise (এর চেয়ে বেশি 20% above the baseline) during an empty furnace state indicates that the insulation layer is damp or the cooling water conductivity is too high.
Ii. Emergency Drying Protocols for Damp Components
If insulation resistance is found to be low, forced drying must be implemented immediately.
দ্য “Internal Heat & External Bake” Method for Coils
- Infrared Lamps & শিল্প Dehumidifiers: Place high-power infrared heating lamps inside and around the furnace shell, baking continuously for 12–24 hours. একই সাথে, deploy industrial-grade dehumidifiers in the workshop to strip moisture from the air.
- Low-Voltage Current Self-Heating:
- Provided the cooling water circulation is normal, output a very low voltage from the power cabinet (সাধারণত 10%–20% of operating voltage). This uses the Joule heat generated by the coil itself to drive out moisture from within.
- দ্রষ্টব্য: This operation requires constant supervision of the leakage current to prevent short circuits caused by localized water accumulation.
Pit and Cable Drainage & শুকানো
- Forced Ventilation: Pits are natural traps for humidity. Use high-power blowers to forcefully exhaust air from the pits, breaking up pockets of stagnant, moist air.
- Desiccant Deployment: Spread quicklime (calcium oxide) or industrial silica gel in non-contact areas of the cable pits to physically absorb moisture.
- Insulation Varnish Reinforcement: After drying cable joints or insulating pillars, apply a layer of anti-arc insulating varnish to enhance surface moisture resistance.
Iii. Rainy Season Emergency Prevention Checklist
To mitigate risks, workshops should implement the following management protocols:
| মাত্রা | কী অ্যাকশন |
| Pit Management | Verify that drainage pumps are functioning; clear silt from gutters to prevent backflow. |
| Cabinet Sealing | Inspect door seals on power cabinets; place silica gel desiccants inside control boards. |
| Restart Protocol | For equipment idle for >24 ঘন্টা, must re-test insulation before startup. না “one-key starts.” |
| Water Management | Control cooling water temperature to avoid the “dew point effect” on the coil surface. |
IV. Procedure After Sudden Arcing
If “পপিং” discharge sounds occur or leakage current spikes during production:
- Immediate Emergency Stop: Cut off the high-voltage power but keep the cooling water circulating.
- Locate the Discharge Point: Inspect the coil refractory for carbonized black spots or flashover marks on insulator surfaces.
- Thorough Cleaning: Use anhydrous alcohol to wipe down carbonized areas, then perform localized drying and varnish repair until insulation resistance returns to normal.
In extreme weather, the cost of preventative testing is far lower than the cost of post-disaster reconstruction. Keeping equipment dry is not just a technical requirement—it is the baseline for production safety.
